New macro `seq-let' in seq.el

New macro `seq-let' in seq.el

[Nicolas Petton]

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Hi,

I just pushed a new macro for seq.el named `seq-let' in the branch
seq-let.

This macro is similar to `cl-destructuring-bind' but provides
destructuring for all sequence types supported by seq.el.

I find this macro quite useful, but I'd like to have some feedback about
it.

Cheers,
Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: New macro `seq-let' in seq.el

[Bozhidar Batsov]

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You've got +1 from me. Great feature!

On 1 May 2015 at 20:37, Nicolas Petton <nicolas@petton.fr> wrote:

> Hi,
>
> I just pushed a new macro for seq.el named `seq-let' in the branch
> seq-let.
>
> This macro is similar to `cl-destructuring-bind' but provides
> destructuring for all sequence types supported by seq.el.
>
> I find this macro quite useful, but I'd like to have some feedback about
> it.
>
> Cheers,
> Nico
> --
> Nicolas Petton
> http://nicolas-petton.fr
>

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Re: New macro `seq-let' in seq.el

[Nicolas Petton]

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Bozhidar Batsov writes:

> You've got +1 from me. Great feature!

I think I'll merge the branch into master and add a TODO to add a pcase
pattern that `seq-let' could wrap instead.

I could also spend some time on it now, but the internals of pcase are
still obscure to me and it will take me some time to grasp it.

PS: `pcase--u1' is pretty long (almost 200 loc), is there any reason not
to refactor it?  As it is now I will have a very hard time understanding
what is does exactly.

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: New macro `seq-let' in seq.el

[Stefan Monnier]

> PS: `pcase--u1' is pretty long (almost 200 loc), is there any reason not
> to refactor it?  As it is now I will have a very hard time understanding
> what is does exactly.

You shouldn't need to know how pcase--u1 works.

You just need to write a pcase-macro which turns (seq ...) patterns into
other (more primitive) pcase patterns.  E.g. it could turn (seq a b)
into a pattern like (and (pred seq-p) (app (elt 0) a) (app (elt 1) b)).


        Stefan

Re: New macro `seq-let' in seq.el

[Nicolas Petton]

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Stefan Monnier writes:

>> PS: `pcase--u1' is pretty long (almost 200 loc), is there any reason not
>> to refactor it?  As it is now I will have a very hard time understanding
>> what is does exactly.
>
> You shouldn't need to know how pcase--u1 works.

I'm not saying that I have to know how it works, only that I find it
hard to understand, and I was wondering if there was a reason for the
function to be so long.


Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: New macro `seq-let' in seq.el

[Stefan Monnier]

> and I was wondering if there was a reason for the function to be
> so long.

It just grew.


        Stefan

Re: New macro `seq-let' in seq.el

[Nicolas Petton]

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Stefan Monnier writes:

> You just need to write a pcase-macro which turns (seq ...) patterns into
> other (more primitive) pcase patterns.  E.g. it could turn (seq a b)
> into a pattern like (and (pred seq-p) (app (elt 0) a) (app (elt 1)
> b)).

Thank you, I'll try to add this soon enough.

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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